RDLC报：错误号加上val()就好了。
=IIF(Val(Sum(Fields!OILRESERVEM1.Value))<>0,CStr(Round(Val(Sum(Fields!OILRESERVEM1.Value))/Val(Sum(Fields!OILRESERVEM1.Value)+Sum(Fields!OILRESERVEM2.Value)+Sum(Fields!OILRESERVEM3.Value))*100,2))+"%","")
